A lubricating structure for rotating-shaft bearings is known that includes (a) a pair of bearings arranged in an axially spaced-apart relationship within a support case for rotatably supporting a predetermined rotating shaft around its axis; and (b) an oil supply port disposed on the support case for supplying lubricating oil for lubricating the pair of bearings to between the pair of bearings. One example of such a structure is disclosed in Patent Documents 1 and 2 which describe a lubricating structure for bearings that rotatably support a drive pinion transmitting rotation from a propeller shaft to a ring gear of a differential mechanism around an axis thereof, wherein lubricating oil splashed by the ring gear is led to the oil supply port to flow into an annular space surrounded by the pair of bearings on the outer circumferential side of a shaft of the drive pinion, to axially penetrate the bearings on both sides to be discharged to the outside, thereby lubricating and cooling the bearings.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-315456
Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-329257